1-16-96

January, 1996 TOKO, Inc.

Page 5

TK701xx

APPLICATION NOTES

RECOMMENDED MOUNTING

Optimum performance can only be achieved when the IC

is mounted on a PC board according to the diagram below.

This is because of the extremely small package and limited

power dissipation. Shape the metal portion of the PCB as

shown in the following drawing.

GND

GND

Use a large bypass capacitor and connect it in a place near

GND of the IC. Pay attention to temperature characteristics

of the capacitor, especially the increase of ESR and de-

crease of capacitance in low temperatures. Oscillation,

reduction of ripple rejection and increased noise may occur

in some cases if the proper capacitor is not used. An output

capacitor more than 1.0

µF is required to maintain stability.

The standard test condition is 3.3

µF (T

DROPOUT VOLTAGE

Dropout voltage is the voltage difference between the input

voltage and the output voltage where the output voltage

decreases to 100 mV below the nominal output voltage as

the input voltage is decreased.

To measure dropout voltage, set the input voltage to the

nominal output voltage +1 V and measure the output

voltage. Reduce the input voltage to the point where the

output is 100 mV below the previously measured value.

The dropout voltage is the difference between the input and

output voltage at this point. This voltage depends on the

load current and ambient temperature.